What are the four devices located under the cover of the system unit?

The four primary devices located under the cover of the system unit are the motherboard, power supply unit, storage devices (such as hard drives or SSDs), and the cooling system (including fans or heat sinks). The motherboard serves as the main circuit board, connecting all components and enabling communication between them. The power supply unit converts electrical power for use by the system, while storage devices provide space for data and programs. The cooling system helps maintain optimal temperatures to prevent overheating of the components.